As is well known and understood, one of the problems in using the troposphere as a communications link for signal frequencies of the order of 1 gigahertz and higher is that the signal reflections will not generally be of constant amplitude. Because the tropospheric link is not homogeneous, the signal reflections change with time, being capable of experiencing at any one interval, a deep fade, a short fade, a more rapid or a less rapid fading of signal level. Where the tropospheric link is used in a switched communications system, as in a trunk multi-channel link, error rates can become prohibitively large. As is also known, a number of methods have been suggested in an attempt to combat these problems of fading--interleaving with error correction coding, automatic repeat request arrangements, and various diversity schemes, such as angle beam diversity or frequency band diversity. However, each of these methods are both costly to implement and complex in their operations, attempting, as they do, to continue the data transmission even during deep fade conditions.